When you undertake to make use of a Windows Vista-based PC behind a firewall device, as well as you undertake to create a non-HTTP network connection, the network connection fails. When the network connection fails, the subsequent programs may stop working or react slowly:

• Microsoft Outlook or Windows Mail
• Web browsers, such as Windows Internet Explorer 7
• Remote Desktop Connection (RDC)
• File sharing programs

When Outlook is exaggerated by this problem, you get the subsequent message in a remote process call (RPC) dialog box:

Outlook is trying to retrieve data from the Microsoft Exchange Server Exchange_Server_FQDN.
Or, you might observe a "Trying to Connect" message in the status bar.

This problem may happen if the firewall device has a trouble with handling the Receive Window Auto-Tuning feature in Windows Vista. This editorial helps you work around this trouble.

Method 1.

Disable auto-tuning and determine whether Windows scaling is handled correctly by the firewall device

To have us stop auto-tuning for you, go to the "Fix it for me" segment. If you would slightly disable auto-tuning physically, go to the "Let me fix it myself" section.

Fix it for me

To stop auto-tuning automatically, click the Fix this problem link. Then, click Run in the File Download dialog box, as well as pursue the steps in this wizard.
Fix this problem

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Note This wizard might be in English only; but, the automatic fix also works for additional language versions of Windows.

Note If you are not on the PC that has the trouble, you can save the automatic fix to a flash drive or to a compact disk, as well as after that you can run it on the PC that has the trouble.

Now go to the "Did this fix the problem?" section.

Let me fix it myself

To disable auto-tuning, follow these steps:

1. Click Start button, and select the All Programs, and afterward click Accessories.

2. Right-click Command prompts, as well as after that clicks Run as Administrator. If you are encouraged for an administrator password or verification, type the password or give verification.

3. At the command prompt, type the subsequent command, and after that press ENTER:
netsh interface tcp set global autotuninglevel=disabled
This command disables the Receive Window Auto-Tuning feature.

4. Close the Command Prompt window.

5. Restart the PC.

Now go to the "Did this fix the problem?" section.

Did this fix the problem?

1. Try to create a non-HTTP network connection. That is, make use of the program that was exaggerated by the trouble.

2. If the trouble is fixed, contact the producer of the firewall device for steps to determine the issue. If the problem is not fixed, you can contact support

3. You can maintain auto-tuning disabled until the trouble is fixed. When you are all set to allow auto-tuning, click Start button, select All Programs, click Accessories, and after that click Command Prompt.

4. At the command prompt, type the subsequent command, and afterward press ENTER:

netsh interface tcp set global autotuninglevel=normal

This command allows Receive Window Auto-Tuning again so that you can acquire benefit of the increase in network throughput performance that this choice provides.